Locking means for preventing accidental disconnection of lighting fixtures



June 1960 f HUBBELL ETAL LOCKING ME S FOR PREVENTING ACCIDENTAL DISCONNECTION OF LIGHTING FIXTURES Filed April 1, 1955 a 0 g f i 47 my 3m 6 2 /4 z 7 p n 5 8 2 m .n 2 2 4 5 z flaw M 00 M a fififl 1 H 3nnentors LGCKING MEANS FOR PREVENTING ACCI- DENTAL DISCONNECTION OF LIGHTING FIXTURES Harvey Hubbell, Long Hill, and Joseph F. Healy, Westport, Conn., assignors to Harvey Huhbell, Incorporated, Bridgeport, Conn, a corporation of Connecticut Filed Apr. 1, 1955, Ser. No. 498,494

2 Claims. (Cl. 33992) This invention relates to electrical fixtures, particularly of the type in which a lighting fixture including a socket for mounting a lamp bulb has means for plugging into 7 a wall outlet receptacle for connecting the lamp contacts therewith, including means whereby the lighting fixture may be locked against separation from the outlet receptacle by relative turning movement between the lighting fixture and the receptacle, and has for an object to provide means tending to maintain the locked position and also releasable locking means for preventing accidental disconnection of the lighting fixture from the receptacle.

Another object is to provide a device of this character in which a soft rubber flange or ring is provided on the lighting fixture to cover and hide the opening in a wall in which the outlet receptacle is mounted with which the fixture is to be used, and also to cover and enclose the front side of the receptacle, together with its mounting means, as well as to cover and close the gap normally present between the lighting fixture and the face of the wall in which the receptacle is mounted.

With the foregoing and other objects in view, we have devised the construction illustrated in the accompanying drawing forming a part of this specification. It is, however, to be understood the invention is not limited to the specific details of construction and arrangement shown, but may embody various changes and modifications within the scope of the invention.

In this drawing:

Fig. l is a transverse section of an electrical fixture of the type involved showing the receptacle mounted in a wall or ceiling, and the lighting fixture secured thereto, the section of this lighting fixture being taken substantially on line 1-1 of Fig. 2;

Fig. 2 is a top plan view of the lighting fixture with a portion of the flange broken away to more clearly show the construction;

Fig. 3 is a transverse section of this fixture ta'ken substantially on line 3-3 of Fig. 2;

Fig. 4 is a detail section showing the means for making the electrical connection from the receptacle to the lighting fixture and locking the contacts of the lighting fixture against withdrawal from the receptacle, and

Fig. 5 is a front view of the mounting or cover plate for the outlet receptacle and showing the contact blades of the lighting fixture in section in the locking position.

This electrical device is shown as mounted in a wall or ceiling comprising the plaster or other type of wall having an opening 11 therein in which is mounted the wall outlet box 12 of any suitable construction such, for example, as a metal box secured in the opening in the wall provided with suitable means, su'ch,for example, as securing screws (not shown) passing through mounting ears or lugs 13 on the box either resting against or recessed into the front'surface of the wall 10, the boxv being provided with an opening or openings 14 which may or maynot be covered by knock-out portions 15 to expose these openings for passage of the usual BX cable (not shown) carrying conductors from the house Wiring Patented June 14, 1960 r ICC system to the outlet box, the cables being secured to the box by the usual means.

Mounted in the box is an outlet receptacle 16 comprising an insulating body 17 having chambers 18 in which are mounted receptacle contacts 19 of substantially U-shaped construction, including spring contact fingers 20 arranged side by side and connected with means, such, for example, as binding post screws 21 for connecting the lead wires 2?. from the BX cable to these receptacle contacts. The front or outer wall of the body comprises a circular boss 34 and has curved slots 23 leading to the chambers 18 in alignment with the spring blades 20 of the receptacle contacts 19 for entrance of the contact blades 24 of an electrical fixture to be connected with the receptacle, such, for example, as a lighting fixture 25. The chambers 18 are wider than the length of slots 23 so that there is provided at one end of each slot a rear- Wardly or inwardly facing shoulder 18a, as shown in Fig. 4, spaced inwardly or back-wardly from the front surface 17a of the receptacle body, for a purpose later to be described, this shoulder for each slot being located at the end of this slot opposite that of the shoulder for the other slot. In the form shown the contact chambers 18 open through the back of the insulating body member 17 and these opensides are covered and closed by the insulating cover plate 26 secured to the body 17 by any 7 suitable means, such, for example as screws 27.

The receptacle 16 is mounted in the wall box 12 by any suitable means, but in the present case is provided with, a substantially U-shaped saddle or yoke 28 extending by the rivets 32. This plate 31 is provided with a central opening 33 in which the circular reduced boss or front Wall 34 of the body member is seated and extends through the plate to the front side thereof. This plate is of a size to cover the open side of the wall box 12 and overlap a short distance on the outer surface of the wall 10 to cover the opening therein. It is secured to the box 12 by any suitable means, but in this arrangement on one side is provided with an elongated slot or recess 35 extending inwardly from one edge of the. plate and on the opposite side with a keyhole shaped opening 36. In mounting this plate together with the receptacle 16, the recess or slot 35 may be inserted under the head of a securing screw 37 in an ear 38 extending inwardly from the side wall of the box 12, and a similar screw in a similar ear (not shown) extending inwardly from the opposite wall of the box may be passed through the larger portion of opening 36 and then the plate turned a short distance to seat the screw in the reduced portion 39 of the opening 36. This provides a simple means for removably mounting the receptacle 16 in the wall box.

The lighting fixture 25 to be used with this receptacle .comprises a body member or housing 40 molded of suitable insulating material, and in the form shown of circular or cylindrical shape, including a cylindrical outer wall 41 and a central cylindrical portion 42 spaced inwardly from the outer wall. and provided with a socket 43 extending inwardly from the outer surface of the outer end wall 44, the inner end of this socket being closed by a transverse wall 45, which is recessed from its rear or innner end by the recesses 46 and 47 to receive thelateral feet or mounting plates 48 and 49 respectively of the contact blades 24 having the wider curved heads 50 and 51 projecting from. the rear surface of the body 25 for insertion in the entrance slots 23 inthe outlet receptacle 16 for engagement with the receptacle contacts 19. Mounted in the socket 43 are lamp contacts eeaipnsingan;"pihntfease a" threaded screwshell 52 having an inwardly extending flange 53 on its inner h end seating against the. bottom oi -the socket 43 and secured therein by r'ivete 54'and'55, (Figs 2 and 3) 'extending through the end wall"45. The rivet 55 also fp'asSes th'ioughthe foot 48 of the blade contact having the head :50 and acts as a means of mounting this blade contact in the may 40' and also providing an electrical connectioh betweenthis contacfa'nd'the screw shell contact 5 2. Also rno'urited ori the end wall 45 is a central contact'SGsecured tothisjwall by the rivet 57 passing "through this walland the foot plate 49015 the blade conf ta ct 24' having the head 51. This rivet therefore also mounts the contact having the he'adSI on the body 40 and forms anlclectrical connection between the central contact 56 andthe'blade'contactfilhaving the head 51.

Thus "when a'l'amp bulb" isscr'ewed into this lighting fixture, its screw "shell contact is threaded into the fixture j shell '52 andits center contact engages the center contact "'56 of thelamp' socket.

"On therear edge of the "outer wall of the body or housing of'thelighting' fixture 25 is provided means for closing the gap between this edge and the wall as well as to cover'and hide'the mountingplate 31 and the mounting lugs for" the wall box 12. This comprises a soft rubber ring'SS; and this ring is tapered so that its 7 free edge 59'is of larger diameter than its opposite edge,

and also'the transverse section of the ring tapers toward this edge so'that the ring is thinner at this edge than at the opp'osite'edgej It may be mounted by any suitable fmeans on the edge of the wall41, but a simple and efiective means is to provide'the edge of the Wall with an annular channel 'or groove 60 and provide the ring 58 with an annular rib61 seatedand fitting into this groove.

This ring is of a width so that whenthe lighting fixture is plugged into the wall outlet receptacle by inserting its 7 contact blades 24- having the heads 50 and 51"into the slots 23 inthe receptacle to engage the-receptacle contacts 19 therein, this ring is compressed somewhat so that its outerfree edge 59 is spread laterally somewhat against'the surface of the Wall10, securing aclose tight fit with this wall and therefore effectively sealing foii the wall box and thereceptacle from the room atmosphere. The resilient action of this ring also helps to retain the lighting fixture iri' interlocked engagement 'with the wall "outlet recepta'cle and resists accidental turning of the lighting fixture to unlock it from thereceptacle. V This flocking efiect' is secured by making the heads" 50 and V 51 of the contact blades 24 wider than the connecting body portions 62, thus forming an overhangin'g shoulder 63 between the outer free end of the blades and the surface 64 of the 'end' wait 45. This shoulder 63 is spacedout'wardly from the end Wall 6ft a sufiicient distance so that after the blade contacts 24 are inserted throughtheslotsf23 into engagement with the receptacle contacts 19thelighting'fixture 25 may be turned about its longitudinal axis to shift'the-shoulder s 63 on these contact blades back or the inwardly facing shoulders 18a in the chambers 18 at one end of each of the slots 23,

' as shown in Fig. 4, and dotted lines 24b in Fig. 5 In other words, the slots 23 are somewhat longer than'the width ot'the heads50 and 51 of'the contact blade 24 to permit these heads to pass through the slots into the receptacle toeng age the receptacle contacts 19 and form felectrical Contact tlierewith, but thereduced connecting fportions 62 of the contact blades permit thern to be shifted longitudinally in theslots 231by a partial turning v movement of'thelighting' fixture 25 to shift these blades in th'e' slots and carry the shoulders 63 of theblades over the shouldersifirz atone end ofeachislot, as indicated in Fig. 4; while still maintaining the electrical contact betweenxthe'blade contacts 24;:and the receptacle con- :"t'a'ctsj'l9, The position of the blade contacts in aligniiidicated the dbttedlines 24a in Fig. 5, and are indi- "e ated iii the locked "positionwith their simmers 63 be? ture from the outlet receptacle. stood the lighting fixture maybe unlocked from the outlet hind shoulders 18a by the dotted lines 24b. As the shoulders 63 of the blades are now behind the shoulders 18a of the receptacle, the blades are securely locked in the receptacle and in*engagement with the receptacle contacts against-withdrawal'from the receptacle, and the lighting fixture is therefore locked in the'receptacleagainst accidental separation therefrom. The shoulders 63 on the blade contacts are securely held in interlocking engagement with the shoulders 18 a in' the receptacle by-the resilient action of the rubber ring 58 which, as previously pointed out, was compressed somewhat when the lighting fixture was plugged into the receptacle. i This rubber ring, therefore, tends tohold the lighting fixture in this interlocked positioriand' tends to resist accidental turning of the lighting fixture in the opposite direction to unlock these-shoulders and permit separation of the lighting fix- That is, it will be underreceptacle and disconnectedtherefrom byfrotating the lighting fixture backwardlyin the opposite direction by a partial turning-movement to carry the-shoulders 63 I, on the contact blades away from behind the shoulders -ceptacle by this reverse turning movement; and thus 18min the; receptacle. This brings the widened heads 50 and 51 again in alignment with the slots 230i the receptacle and will permit withdrawal of these blades from the receptacle and'therefore permit detachment of the lighting fixture from-the receptacle. However, further means is provided for preventing accidental unlocking of the lighting fixture from the reprevent accidentalseparationof the lighting fixture from the receptacle. This is a positive locking means which is manually set and released by the operator. Asimple and elfective' form is shown comprising a screw-65 threadedly mounted in a rivet or sleeve 66 molded in a thickened wall portion 67 at the inner side of the side wall 41 and the end wall 4-2 of the body member-40, and the mounting plate 31 of-the-receptacle isprovided with a-pair of openings 68 arranged at-diametrically opposite sides of the'plate inalignment with this screw when the lighting fixture 25 has been turned to the locking'position after insertion of the blade contacts 28 into 'the receptacle. This screw may then be manipulated by a screw driver or other im'plement as its head 69 is accessible at the front of thebodymember 40 and it may be screwed inwardly to pass its inner-end 70'through the hole 68 in the plate 31in alignment therewith. This positively locks the lighting fixture 25 in the locked position in the receptacle and'preventsany chance ofaccidental separation of the -lighting-fixturefrom the wall and the receptacle. However, should it become desirable to remove the lighting fixture for any reason, this-may be -done by retracting the screw to remove itsinnerend from thehole 68 in thezplate 31 which will 'unlock thefixture' from --this plate and will-permit it'being-turned backwardly or in a reverse direction to=remove-theshoulders 63 ot'the contact blades 24'from behindtheshoulders 18a in the receptacle,- ,and 'permit'withdrawal of the blades from their receptacleand therefore-separation of the lighting fixture-from the receptacleand'the wall on which it is mounted.

From the above it-"will be seen that the lighting fixture may be 'plugged'intotbe' wall outlet receptacle by'the --simple operation of -ihsertingits blade'contacts'24'into --the'curved slots 23 '-in'='the receptacle into engagement back of the shoulders =18a in the receptacle-to positively ilock the'lighting fixture to the receptacle and prevent its withdrawal therefromuntil'thei lighting fixture is turned a; similar amount in the reverse 'or' counterclockwise direction to unlock the lighting fixture by shifting the shoulders 63 of the contact blades away from shoulders 18a of the receptacle. As previously indicated, when the lighting fixture is plugged into the receptacle, the electrical circuit in the receptacle and the lighting fixture is established by the blade contacts of the fixture engaging the receptacle contacts, and this electrical contact is maintained during movements of the lighting fixture both to and from the locked position. As the rubber ring 58 is compressed somewhat, when the lighting xture is plugged into and locked to the receptacle it will retain the shoulder 63 in engagement with the shoulder 18a, will also tend to resist accidental turning movement of the lighting fixture in a reverse direction to unlock it. However, the lighting fixture may be positively locked in the locked position and against this reverse movement by operating screw 65 to pass its inner end through one of the openings 68.

Having thus set forth the nature of our invention, we claim:

1. In an electric fixture, a wall outlet receptacle including an insulating body member and receptacle contacts in said member, said body provided with contact blade entrance slots in its front Wall leading to said contacts, means for mounting said receptacle in a Wall box including a cover plate for the front side of the box provided with a noncentrally located opening therein, a lighting fixture including a housing member, lamp contacts in said housing member for mounting a light bulb, blade contacts connected with, the lamp contacts and projecting rearwardly from said housing member for insertion in the receptacle for engagement with the receptacle contacts, said housing member and contact blades adapted for relative limited turning movements in the receptacle after said blade contacts are inserted therein, cooperating locking means in the receptacle and on the contact blades adapted to become effective by turning movement of the lighting fixture in one direction ofter insertion of the contact blades into the receptacle to prevent withdrawal of the blade contacts from the receptacle, and a locking screw carried by and extending longitudinally of the housing member so located as to be in alignment with the opening in the cover plate after the lighting fixture has been turned to the locking position, said screw including manually operable means at its outer end whereby it may be operated to either advance the screw to insert its inner end in said opening in the cover plate to lock the lighting fixture against turning movement in the opposite direction to release the locking means or to withdraw the screw from said opening to permit said movement to release the locking means.

2. In an electric fixture, a mounting Wall having an opening therein, a wall outlet receptacle mounted in the opening including an insulating body member and receptacle contacts in said member, said body provided with contact blade entrance slots in its front wall leading to said contacts and inwardly facing shoulders in the chambers at one end of the slots, means for mounting said receptacle in a wall box in said opening including a cover plate for the front side of the box provided with a noncentrally located opening therein, a lighting fixture including an insulating housing member including a circular outer side wall having a free inner edge, lamp contacts in said housing member for mounting a lamp bulb, blade contacts connected with the lamp contacts and projecting rearwardly from the housing member for insertion in the receptacle through said slots for engagement with the receptacle contacts, said blade contacts having forwardly facing shoulders adapted to be shifted to a position over the shoulders in the receptacle by relative turning movement of the lighting fixture after insertion of the blade contacts into the receptacle to lock the lighting fixture against withdrawal from the receptacle, a resilient flexible ring of rubber-like material secured to the free inner edge of the housing member and extending rearwardly therefrom and compressed between this member and the mounting Wall, said ring being flared outwardly and rearwardly from the housing mem her and tapered in cross section with its thinner edge the free edge engaging the surface of said mounting wall, said ring by its resilient action tending to shift the lighting fixture away from the receptacle and retain the shoulders on the blade contacts in looking position against the shoulders in the receptacle, and a locking screw carried by and extending longitudinally of the housing member so located as to be in alignment with the opening in the cover plate after the lighting fixture has been turned to the locking position, said screw including manually oper able means at its outer end whereby it may be operated to either advance the screw to insert its inner end in said opening in the cover plate to lock the lighting fixture against turning movement in the opposite direction to release the locking means or to withdraw the screw from said opening to permit said movement to release the locking means.

References Cited in the fileof this patent UNITED STATES PATENTS 445,954 Jordan Feb. 3, 1891 491,596 Robb Feb. 14,1893 1,509,839 Kuhn Sept. 30, 1924 1,603,255 Hubbell Oct. 12, 1926 2,054,497 Doherty Sept. 15, 1936 2,069,238 Fraser Feb. 2, 1937 2,138,735 Ellis Nov. 29, 1938 2,446,971 Wittig Aug. 10, 1948 2,712,120 Cochran June 28, 1955 

